Custom GHCi driver is painfully slow

Summary

I'm inclined to write a custom ghci that has support for a custom DSL. I used https://gitlab.haskell.org/ghc/ghc/-/tree/ghc-9.6.2-release/ghc as a starting point.

However, a custom build of the ghc main driver behaves painfully slow when loading libraries. This is even the case without any modifications to the source.

Not sure what I'm doing wrong here. Any help is greatly appreciated.

Steps to reproduce

$ wget https://downloads.haskell.org/~ghc/9.6.2/ghc-9.6.2-src.tar.xz
$ tar xvf ghc-9.6.2-src.tar.xz
$ cd ghc-9.6.2/ghc/
$ mv ghc-bin.cabal.in ghc-bin.cabal
$ sed -i 's/@ProjectVersion@/9.6.2/' ghc-bin.cabal
$ sed -i 's/@ProjectVersionMunged@/9.6.2/' ghc-bin.cabal
$ cabal configure --enable-optimization -finternal-interpreter
$ cabal build

$ time $(cabal list-bin ghc) -B$(ghc --print-libdir) -e '' -package ghc -v3
...
Loading unit ghc-9.6.2 ...        <-- !!! THIS IS SLOW !!!
...
real    0m9.459s
user    0m9.185s
sys     0m0.247s

$ time ghc -e '' -package ghc -v3

real    0m0.060s
user    0m0.045s
sys     0m0.015s

Note that:

• From what I tried, only --interactive/-e seems to be slow. Normal compilation is swift.
• -v3 reveals that loading packages / libraries seems to be slow.

Expected behavior

The custom driver and ghc should behave similar, performance wise.

Environment

• GHC version used: 9.6.2
• Operating System: Linux
• System Architecture: x86-64